JPS59129856A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body superior in electric stability, strength, durability against repeated uses, etc. by forming on a conductive substrate a photosensitive layer contg. zinc oxide, a thermoplastic aromatic polyacrylate and a specified org. compd. as effective components. CONSTITUTION:An intended electrophotographic sensitive body is obtained by forming on a conductive substrate of an aluminum plate or the like a photosensitive layer contg. as effective components (A) 100pts.wt. zinc oxide; (B) a thermoplastic aromatic polyester, such as poly-2,2-propanebis(4-phenyl)isophthalate- terephthalate coester, expressed by formula I , n being 20-300, and (C) >=5pts.wt. compd. represented by formula II in which R1-R4 are each H, alkyl, or the like; R5, R6 are each H, alkenyl, or the like; R7, R10 are each H, hydroxyl, or the like: such as 1,1-bis(4-N,N-dimethylaminophenyl)-1-phenylmethane.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic photoreceptor, particularly an electrophotographic photoreceptor containing zinc oxide as a photoconductive substance.

Photoconductive materials such as amorphous selenium alloys, zinc oxide, cadmium sulfide, and organic photoconductors (OPCs) have traditionally been used in electrophotographic photoreceptors. Among these, zinc oxide has the following properties: its raw materials and photoreceptor are non-toxic, its price is low, it can be produced using traditional coating technology, it can be easily made into a large area, its image quality is good, and its color sensitivity It has a number of characteristics, such as being able to control polarity, having charging ability and photoresponsiveness for both positive and negative polarities. Further, in recent years, the human body and environmental pollution of chemical substances has become a problem, and photoreceptors are no exception to this problem. Zinc oxide is the only photoreceptor currently in practical use that has been confirmed to be non-polluting, including raw materials, and from this point of view, zinc oxide has recently been reevaluated.

Conventionally, zinc oxide photoreceptors have been produced by providing a photoconductive layer on a conductive support, which is made of zinc oxide powder sensitized with an organic dye sensitizer and an organic polymer having binding ability.

The electrophotographic properties of a zinc oxide photoreceptor depend on the types of zinc oxide, dye sensitizer, and resin binder that constitute the photoconductive layer, and the blending ratio of these constituent materials. All resin binders used in zinc oxide photoreceptors contain a certain amount of electron-accepting polar groups such as carboxyl groups, hydroxyl groups, epoxy groups, and silanol groups. These polar groups interact with the zinc oxide surface to improve the dispersion fluidity of the photoconductive layer coating solution. Furthermore, in the formed photoreceptor, the interaction between the zinc oxide surface and the polar group governs the adhesion efficiency of corona discharge charges and the photocarrier generation efficiency during light irradiation. Regarding the blending ratio of the resin binder, if the blending ratio of the resin binder to zinc oxide is too low, the potential stability during repeated use and the mechanical strength of the photoreceptor coating will decrease. On the other hand, if the blending ratio of the resin binder is too high, practical photosensitivity cannot be improved. For the above reasons, it is essential that the resin binder conventionally used in zinc oxide photoreceptors contains a certain amount of electron-accepting polar groups such as carboxyl groups, hydroxyl groups, epoxy groups, and silanol groups.
Furthermore, the blending ratio of the resin binder to zinc oxide has been limited to a range of 10 to 4% by weight and 11'L% to the zinc oxide.

The biggest drawback of the zinc oxide photoreceptor is that its repeated durability is extremely short. Selenium photoreceptor or sulfiding power [・
While the aluminum photoreceptor has a durability of 20,000 to 100,000 sheets, the zinc oxide photoreceptor has a durability of 500 to 2,50 sheets.
I don't like 0 pieces.

The reasons for the short durability of zinc oxide photoreceptors include electrical, chemical, and photochemical mechanisms caused by repeated charging and exposure, and physical and mechanical mechanisms caused by repeated development, transfer, and cleaning. One example is the physical mechanism.

The former includes: ■ current deterioration due to corona discharge current, ■ oxidative deterioration of dyes and binders due to ozone, ■ oxidative deterioration of dyes and binders due to doublet oxygen, and ■ dye and binding due to photogenerated holes. The latter is caused by oxidative deterioration of the dye and binder caused by OH radicals, and the latter is caused by: destruction of the photoconductive layer surface by the developer, transfer paper, and cleaner, and toner filming. be. A photoreceptor that has deteriorated due to such factors (・1
The surface potential decreases, the dark decay rate increases, the sensitivity L5 decreases, the residual potential increases, and the pre-exposure effect becomes noticeable, and the image shows a decrease in density, occurrence of fogging, decrease in contrast, occurrence of afterimages, and occurrence of white spots. be observed. The surface of the photoreceptor fades due to deterioration of the dye. Among the various factors mentioned above, those that govern the durability of zinc oxide photoreceptors are deterioration of the dye sensitizer and mechanical destruction of the photoreceptor surface.

In view of the above points, many techniques have been proposed in recent years to improve the repeated durability of zinc oxide photoreceptors. For example, ■ forming a capsule wall containing a dye sensitizer on the surface of zinc oxide (
Japanese Patent Application Publication No. 1983. -99635, JP-A-55-89845, etc.), ■ Providing an insulating protective layer on the zinc oxide photoconductive layer (JP-A-57-19780, etc.), ■ Increasing the blending ratio of the resin binder (JP-A-55-89845, etc.). 56-6514.1, etc.), and (2) using poly-N-vinylcarbazole (PvK) as a resin binder (Japanese Patent Application Laid-open No. 5.6-124) 746, etc.). However, various problems still exist in the above-mentioned techniques. For example, in (2), the permissible range of capsule wall forming conditions for obtaining good photoreceptor characteristics is narrow, and in (2), in order to form an electrostatic latent image on the photoreceptor, for example, U.S. Patent No. 3,041,167 No., Special Publication No. 19748, Special Publication No. 25223, No. 42,
Special Publication No. 43-1552, Special Publication No. 47-17871,
It is necessary to use the technology disclosed in Japanese Patent Publication No. 48-2965, etc., and the process of the copying machine becomes complicated. In addition, the characteristics of (1) and (2) are still insufficient in terms of repeated durability and photosensitivity, respectively.

A second problem with zinc oxide photoreceptors is their applicability to various cleaning mechanisms, particularly blade cleaning systems. Zinc oxide photoreceptors usually have 10
Contains ~50% voids and 2~10μ on the surface of the photoconductive layer.
It has a non-uniform structure with unevenness of m. For this reason, zinc oxide photoreceptors have low mechanical strength, and it has been difficult to apply a blade cleaning method to them.

The third problem with zinc oxide photoreceptors is photosensitivity. A photosensitive layer in which a photoconductive pigment such as zinc oxide is dispersed in a resin binder has a so-called photodischarge induction effect, which causes a delay in the decay of the surface potential immediately after irradiation with light, which causes a decrease in sensitivity. (Kitamura, Journal of the Komon Electronic Photography Society, Vol. 20, p. 60 (1982)).

It is still possible to provide a zinc oxide photoreceptor with chargeability and photoresponsiveness for both positive and negative polarities, and conventionally, for example, the following techniques have been known.

1) Using nitrous oxide heat treated in hydrogen sulfide (US Pat. No. 3,060,134).

2) Use zinc oxide heat-treated in the presence of hydrogen sulfide and ammonia gas (Japanese Patent Publication No. 53-20856).

3) Incorporating an inorganic acid salt of manganese or cobalt into the photoconductive layer (Japanese Patent Publication No. 52-3303).

4) Including an organic manganese compound in the photoconductive layer (Photograph Inc. Science and Engineering Vol. 16, p. 231, 1972) 5) 50-9
A copolymer compound containing 5% acrylic acid alkyl ester and 1 to 5% organic acid having a vinyl group is used as a binder (Japanese Patent Publication No. 51-16148).

The following is known as a technique for imparting positive charging ability and photoresponsiveness to a zinc oxide photoreceptor in a housing.

6) A photoreceptor with a laminated structure consisting of a charge generation layer containing a sensitizing dye and a charge transport layer in which zinc oxide powder is bonded with a resin having a refractive index of 1.59 or more (Japanese Patent Laid-Open No. 55-60953).

However, all of the listed prior art techniques 1) to 6) have problems in manufacturing and/or in the characteristics of the photoreceptor. For example, in 1) and 2), zinc oxide is also treated with a toxic substance called hydrogen sulfide, so special manufacturing equipment is required, and the allowable range of zinc oxide treatment conditions to obtain good photoreceptor characteristics is extremely narrow. For example, in 3) and 4), photosensitivity decreases when the amount of additive is increased to impart positive charging ability, in 5), photosensitivity is slow, and in 6), the charge generation layer and The problem is that it is difficult to manufacture because a layered structure consisting of a charge transport layer is provided by coating.

In particular, a characteristic problem common to the conventional technology is that the photosensitivity of the photoreceptor is slow, so the practical use of the photoreceptor is limited to photosensitive paper for direct method copying machines, and PPC method copying machines that can be used repeatedly. It has not been applied to photoreceptors, etc.

In view of the above-mentioned circumstances, the present applicant has arrived at the present invention as a result of intensive studies aimed at solving various problems with zinc oxide photoreceptors.

That is, the objects of the present invention are: 1) A zinc oxide photoreceptor with excellent electrical stability, chemical stability, and mechanical strength, and significantly improved repeat durability. 2) A zinc oxide photoreceptor that is compatible with a blade cleaning mechanism. Photoreceptor 3) Highly sensitive zinc oxide photoreceptor that shows no induction effect on photodischarge 4) Zinc oxide photoreceptor that has both positive and negative polarity chargeability and photoresponsiveness 17 and excellent repeated durability 5) Special material Another object of the present invention is to provide a zinc oxide photoreceptor that does not require any special manufacturing process, has excellent repeat durability, and has both positive and negative polarity chargeability and photoresponsiveness.

The above-mentioned objects of the present invention are as follows: 1. An electrophotographic photoreceptor having at least a photosensitive layer provided on a conductive support, wherein the photosensitive layer is made of zinc oxide and the formula (I) H3 (where n is an integer of 20 to 200). ), and a thermoplastic aromatic polyarylate represented by the general formula (n) (wherein R1, R2, R3, and R4 are hydrogen atoms, substituted or unsubstituted alkyl groups, cycloalkyl groups, and alkenyl groups). or an aryl group, R5 and R6 are hydrogen atoms,
Substituted or unsubstituted alkyl group, cycloalkyl group, alkenylcycloalkenyl group or aryl group, R7
, R8, R9, and RIO represent a hydrogen atom, a hytroquine group, a substituted or unsubstituted alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, an alkoxy group, or an amine group, and R5 and R6 are cyclized with each other. may form a saturated or unsaturated hydrocarbon ring having 3 to 10 carbon atoms. ) An electrophotographic photoreceptor comprising a compound represented by the following as an active ingredient.

2. The electrophotographic photoreceptor according to claim 1, wherein the compound represented by formula (1) is blended in an amount of 5 parts by weight or more per 100 parts by weight of zinc oxide.

achieved by. The present invention will be explained in detail below.

As a result of detailed studies on resin binders for zinc oxide photoreceptors, the applicant found that the formula (1) has a significantly low content of electron-accepting functional groups such as carboxyl groups, hydroxyl groups, epoxy groups, and silanol groups. However, a thermoplastic aromatic polyarylate represented by n is an integer of 20 to 200 is used as a binder, and a compound represented by the general formula (II) (hereinafter abbreviated as compound (II)) is used as a binder. It was discovered that a zinc oxide photoreceptor prepared by compounding a compound (2) exhibits characteristics significantly different from those of conventional zinc oxide.
■)/varies in proportion to the weight ratio of zinc oxide.

2) The photosensitivity of the photoreceptor under positive and negative charging is different from that of the compound (
It is improved by adding II).

Furthermore, the photosensitivity under positive and negative charging is determined by adjusting the weight ratio of polyarylate/zinc oxide to 5/1oo to 20%o.

Even if it is varied between 0, it does not change.

3) The induction effect of photodischarge disappears.

The above discoveries are based on zinc oxide, polyarylates and the compound (
II) as an active ingredient, and when conventionally used resins such as acrylic, silicone, epoxy, vinyl chloride-vinyl acetate copolymer, etc. are used as a binder. was not observed.

Preferred polyarylates for the present invention are as shown below.

B1 PoIJ-2.2-propane bis(4-phenylinophthalic acid-conistere terephthalate) B2. Poly-2.2-propane bis(4-phenyl terephthalate) B3. Poly-2,2-propane bis(3,5-dichloro-4-phenylisophthalic acid-terephthalic acid conister) B4 Poly-methane bis(4-phenylisophthalic acid-terephthalic acid conister) These polyarylates are, for example, 22-bis (4-hydroxyphenyl)propane or bis(4-hydroxyphenyl)methane and an acid chloride of phthalic acids such as phthalic acid, isophthalic acid, terephthalic acid, etc. are subjected to interfacial condensation polymerization in the presence of an alkali or 2.2-bis(4-hydroxyphenyl)propane or bis(4-hydroxyphenyl)methane is It can be easily obtained by known synthesis methods such as melt polymerization of (4-hydroxyphenyl)propane or bis(4-hydroxyphenyl)methane and esters of phthalic acids.

Next, specific examples suitable for the present invention as compounds represented by the general formula (II) are listed below.

C1,1,1-bis(4-N,N-dimethylaminophenyl)-1-phenylmethaneC2,1,,1-bis(4-N,N-dimethylamino-
2-methylphenyl)-1-phenylmethane C3,1,1-bis(4-N,N-dimethylamino-2
-methylphenyl)-1-(2-chlorophenyl)methaneC4,1,1-bis(4-N,N-dimethylamine-
2-methylphenyl)-1-(4-methoxyphenyl)
Methane C5,1,1-bis(4-N,N dimethylaminophenyl)-1-(4-hydroxyphenyl)methane C
6,1,1-bis(4-N,N-dimethylaminophenyl)-1-('2.4dimethoxyphenyl)methane C7
, 1,1-bis(4-N,N-dimethylamino-2-ethylphenyl)-1-phenylmethane C8,1,1-bis(4-N,N-dimethylamino-2
-methoxyphenyl)-1-phenylmethane C9,1,1-bis(4-N,N-dimethylamino-2
-ethoxyphenyl)-1-phenylmethane CIo, 1.1-bis<4-N,N-diethylaminophenyl)-1-7enylmethane CIl, 1.1-bis(4-N,N-diethylamino-2-methyl phenyl)-1-phenylmethane CI2. 1.1-bis(4-N,N-diethylamino-2-methylphenyl)-1-(2-chlorophenyl)
Methane CI3. 1.1-bis(4-N,N-diethylamine-2-methylphenyl)-1-(4-methoxyphenyl)methane CI4. 1.1-bis(4-N,N-
diethylaminophenyl)-1-(4-hydroxyphenyl)methane C15,1,1-bis(4-N,N-diethylaminophenyl)-1-(2,4-dimethoxyphenyl)methane CI6. 1.1-bis(4,-N,N-
Diethylamino-2-ethylphenyl)-1-phenylmethane CI7. 1.1-bis(4-N,N-diethylamino-2-methoxyphenyl)-1-phenylmethane CI8. 1.1-bis(4-N,N-diethylamino-2-ethoxyphenyl)-1-phenylmethane C19,1,1-bis(4,-N,N-diethylamino-2-methylphenyl)-1-( '2.6-)chlorophenyl)methaneC20,1,1-bis(4-N,N-diethylamino-
2,5-dimethoxyphenyl)-1-phenylmethane C
21,1,1-bis(4-N,N-dibenzylaminophenynoly-1-phenylmethaneC22,1,1-bis(4-N,N-dibenzylamino-2-methylphenyl)-1- Phenylmethane C23,1,1-bis(4-N,N-dibenzylamino-2,5-dimethylphenyl)=1-phenylmethane C
24,1,,1-bis(4-N,N-dibenzylamino-2-methoxyphenyl)-1-phenylmethane C25
,1,1-bis(4-N,N-dimethylamino-2-methylphenyl)-1-(2,4-dimethoxyphenyl)
MethaneC26,1,1,1-)Lis(4-N,N-dimethylaminophenyl)-1-phenylmethaneC27,1,1,1-Tris(4-N,N-dimethylamino-2-methylphenyl ) Methane C28,1,1-bis(4-N,N-diethylamino-
25-dimethylphenyl) -1-(4-N,N-dimethylaminophenyl)methane C29,1,1-bis(4-N,N-diethylamino-
2-methylphenyl)-1=(4-N,N-dimethylamino-2-chlorophenyl)methaneC30,1,,1-bis(4-N,N-diethylamino-2-methylphenyl)-1-( 4-N,N-dimethylamine-2-methylphenyl)methane C31,1,1-bis(4-amino-2-methylphenyl-(4-N,N-dimethylaminophenyl)methane C
32. 1. 1-bis(4--amino-2.5-
dimethylphenyl)-1-(4-N,N-dimethylaminophenyl)methane C33,1-(4-N,N-dimethylaminophenyl)-1,1,1-triphenylmethane C34,1-(4- N,N-diethylaminophenyl)
-1,1,1-triphenylmethane C35,1,1-bis(4-N,N-dimethylaminophenyl)-181-diphenylmethane C36,1,1-bis(4-N,N-diethylami, l
phenyl)-11-diphenylmethane C37,1,1-bis(4-N,N-dibenzylamino-2-methylphenyl)-1-cyclohexylmethane C
38,1,1-bis(4,-N,N-dibenzylamino-2-methoxyphenyl)-1-cyclohexylmethane C39,1,1-bis(4-N,N-dibenzylaminophenyl)-1 -Cyclohexylmethane C40,1,1-bis(4-N,N-dibenzylamino-25-dimethylphenyl)-1-cyclohexylmethane C41,1,1-bis(4-N,N-dibenzylamino-25 -dimethoxyphenyl)-1-cyclohexylmethane C42,1,1-bis(4-N,N-gelamine/
-2-Mef-phenyl)-1-(4-N,N-diethylaminophenyl)methane C43,1,1-bis(4-N,N-diethylamino-
2-methylphenyl)hebutane C44,1,1-bis(4-N,N-diethylamino-
2-methoxyphenyl)-2-methylpropane C4,5,t,il-tris(4-N,N-diethylamino-2-methylphenyl)methane C46α,α,α′,α′-tetrakis(4-N, N-
diethylamino-2-methylphenyl)-p-ky/leneC47,1,1-bis(4-N,N-diethylamino-
2-ethylph, enyl)-2-phenylethaneC4,8,1,1,5,5-tetrakis(4-N,,N
-dimethylamine-2-methylphenyl)pentane C49,1,1-bis(4-N,N-diethylamino-
2-ethylpheny/l')-4-,7'thylcyclohexane C50,1,1-bis(4-N,N~dimethylamino-2-methylphenyl)cyclohexane C51,1,1-bis(4-N- Ethyl-N-methylamino-2-)-3-methylcyclohexane C52,1,1,2,2-tetrakis(4-N,N-
Dimethylamine-2-methylphenyl)ethane C53,1,1-bis(4-N,N-diethylamino-
2-methylamino/l/ ) -3-phenylpropane C54,1,1-bis(4-N,N-dibenzylamino-2-methylphenyl)pentane C55,1,,1-bis(4-N, N-dibenzylamino-2-methoxyphenyl)-2-methylpropane C5
6,1,1-bis(4-N,N-dibenzylamino-2
-methylphenyl) cyclohexane C57,1,1-bis(4-N,N-dibenzylamino-2-methylfugonyl)propane C58,1,1-bis(4-N,N-dibenzylamino-2-methylphenyl ) Normanbutane C59,1,1-bis(4-N,N-dibenzylamino-2-methoxyphenyl)propane C60,1,1-bis(4-N,N-dibenzylamino-2-methoxyphenyl) Normanbutane C61,,1,1-bis(4-N,N-diethylaminophenyl)butane C62,1,1-his(4-N,N-dimethylaminephenyldi-2-methylpropane C63,1,1 -bis(4-N,N-dibenzylaminophenyl)pentane C64,1,1-bis(4-N,N-dibenzylaminophenyl)=2-methylpropane C65,1,1-bis(4-N , N-dibenzylaminophenynolycyclohexane C66, 1,1-bis(4-N,N-dibenzylaminophenyl)propane C67, 1,1-bis(4-N,N-dibenzylaminophenyl)normanbutane C6B, 1,1-bis(4-N,N-dibenzylamino-2,5-dimethylphenyl)butaneC69,1,1-bis(4-N,N-dibenzylamine-25-dimethylphenyl) Normanbutane C70,1,1-bis(4-N,,N-dibenzylamino-25-dimethoxyphenyl)Normalbutane C71,1,1-bis[:4-N,N-di(p-tolyl)amino phenyl] hexane C72,2,2-bisC4-N,N-di(p-tolyl)
[aminophenyl]propaneC73,1,]-bis[4-N,N-di(p-1-zyl)aminophenyl-1-phenylethaneC74,,1,1-bisC4,-N,N-di( p-tolyl)aminophenyl]-1,1-phenylethane C75,1,1-bis[4-N,N-di(p-tolyl)aminophenylcomethane C7611-bis(4-N,N-di (p-tolyl)aminophenyl-1-phenylmethane C77,,1,1-bis[:4-N,N-di(p-tolyl°)aminophyl:]-4-tert-butyrunclohexane C78 ,1,1-bis[:4-N,N-di(-monotolyl)aminophenyl-2-methylpropaneC79,1,1-bisC4-N,N-di(p-tolyl)
aminophenyl]ethane C80,1,1-bis(4-N,N-di(p-tolyl)
Aminophenyl-3-methylbutane C81,1,1-bis[:4-N,N-di(p-tolyl)amino-2-methylphenyl]ethane C82,1,1-bis[4-N,N-di (p-tolyl)
Amino-2-methylphenylcocyclohexane C83,1,1-bis(4-N,N-dibenzylaminophenynoriethane C84,1,1-bis(4-N,N-dibenzylaminophenynolipropane C85, 1,1-bis(4-N,N-dibenzylaminophenyl)n-butaneC86,1,1-bis(4-N,N-dibenzylaminophenyl)-2-methylbutaneC87,1,1-bis( 4-N,N-dibenzylaminophenyl)-n-hexane C88,1,1-bis(4-N,N-dibenzylaminophenyl)=2-ethylhexane C89,1,,1-bis(4- N,N-dibenzylaminophenyl)-n-dodecane C90,1,'l-bisC4-N,N-di(p-chlorobenzyl)aminophenyl]ethane C91,1,1-bis[:4-N , N-di(0-chlorohensyl)aminophenyl-n-butane C92,1,1-bis[:4-N,N-di(p-bromobenzyl)aminophenyl-n-butane 093, 1,1-bis [:4-N,N-di(p-methylbenzyl)aminophenyl]propane C94,1,'l-bis[4-N,N-di(p-nitrobenzyl)aminophenyl]-2-ethylhexane C9
5,1,1-bis(4-N,N-dibenzylamino-2
-methylphenyl)methane C96,1,1-bis(4-N,N-dibenzylamino-2-ethylphenyl)methane C97,1,1-bis[4-N,N-di(p-chlorobenzyl) Amino-2-ethylphenylcomethane C98,1,1-bis(4-N,N-dibenzylamino-2-methylphenyl)ethane C99,'1,1-bis(4-N,N-dibenzylamino -2-ethylphenyl)ethane Cl00. 1.1-bis(4-N,N-dibenzylamino-2-methylphenyl)propane C1'01. 1.1-bis(4-N,N-di(0-chlorohensyl)amino-2-ethylphenyl)propaneClO2,1,1-bis(4-N,N-dibenzylamino-2-methylphenyl)butane C103,],,]1-bisI:4-N,N-di(
p-chlorobenzyl)amino-2-ethylphenylcobutane ClO4,1,1-bis(4-N,N-dibenzylamino-2-methylphenyl)-2-methylpropane ClO
3,1,1-bis(4-N,N-dibenzylamino-2
-methoxyphenyl)butaneC106,1,1-bis(4-N,N-dibenzylamino-2-methylphenyl)butaneC107,1,1-bisC4-N,N-di(p-tolylamine)- 2-Methoxyphenyl]hebutaneC1,08,1,1-bis(4-N,N-dibenzylamino-2=methylphenyl)hexaneC109,2,2-bis(,4-N,N-dibenzylamino) -2-methylphenyl)butane C110,2,2-bis(4-N,N-dibenzylamino-2-methylphenyl)propane The electrophotographic photoreceptor of the present invention includes a dye sensitizer, zinc oxide powder,
A photoconductive layer coating solution is prepared by uniformly mixing and dispersing a mixture consisting of the polyarylate, the compound represented by general formula (II), and a dispersion solvent, and this coating solution is applied onto a conductive support and dried. difference.

It is created by

Conductive supports include metal plates such as aluminum, nickel, and chromium; metals such as aluminum, nickel, and palladium deposited or sputtered on paper stock or plastic films; metal foils such as aluminum and paper; Materials such as laminated plastic films, carbon-mixed paper, low-resistance paper treated with organic or inorganic conductive treatment agents, glass plates or plastic films with transparent films such as tin oxide and/or indium oxide can be used. can. The shape of the conductive support can be selected from a sheet, a long roll, an endless belt, a drum, etc.

In principle, the photoreceptor of the present invention is constructed by providing a photoconductive layer made of the above-mentioned zinc oxide powder, polyarylate, and a compound represented by the general formula C11) on a conductive support. However, it is also very useful to provide an intermediate layer between the conductive support and the photoconductive layer. This intermediate layer prevents free carriers from transferring from the conductive support to the photoconductive layer, and also acts as an adhesive layer to hold the photoconductive layer integrally and adhesively bonded to the conductive support.

Furthermore, it also has a buffering effect to prevent dielectric breakdown of the photoconductive layer due to corona discharge overcurrent during corona charging.

Materials for this intermediate layer include gelatin, casein, starch,
Aqueous polymeric substances such as polyvinyl alcohol, polyvinylpyrrolidone, carboxymethyl cellulose, hydroxypropyl cellulose, water-soluble polyvinyl butyranope polyacrylic acid, polyethyleneimine, polyethylene glycol, and polypropylene glycol can be used. The thickness of the intermediate layer is suitably in the range of 0.5 to 10 μm.

As the zinc oxide powder constituting the photoconductive layer, those conventionally used in electrophotographic photoreceptors can be used as is.

As the spectral sensitizer for zinc oxide, conventionally known triphenylmethane dyes, xanthine dyes, thiazine dyes, azine dyes, xanthine dyes, and the like can be used. Among these, dye compounds having a xanthine skeleton or triphenylmethane skeleton and having a capable acid group or a lactone ring are preferred from the viewpoint of solubility and adsorption to zinc oxide.

Particularly suitable dye sensitizers include dibromefluorescein, short fluorescein, tetrachlorofluorescein, butrabromofluorescein, tetraiodofluorescein, tetrachlortetraiodofluorescein,
Examples include tetrabromtetraiodofluorescein, bromophenol blue, tetrabromophenol blue, tetraiodophenol blue, bromthymol blue, bromcresol blue, and bromcresol green.

The amount of dye sensitizer added to zinc oxide is 100% zinc oxide.
Effective is 10-3 parts by weight to 5 parts by weight,
A particularly preferable addition amount is 10-2 parts by weight to 2 parts by weight. Known techniques can be used to adsorb the dye sensitizer onto zinc oxide. Zinc oxide is added to a solution in which the pigment is dissolved in a suitable solvent, and this coating solution is thoroughly mixed and dispersed using a ball mill etc. to adsorb the pigment onto the surface of the zinc oxide.Then, the solvent of the pigment solution is removed from this coating solution. However, a method of preparing a zinc oxide powder (hereinafter abbreviated as sensitized zinc oxide) on the surface of which a dye is adsorbed is a suitable dye adsorption method for the present invention. As a method for removing the solvent of the dye solution, any of the methods such as filtering, heating drying, freeze drying, spray drying, or the technique disclosed in Japanese Patent Publication No. 39819/1986 is effective.

The dispersion solvent used for preparing the photoconductive layer coating solution is preferably a solvent for polyarylate and a compound represented by the general formula (I), such as tetrahydrofuran, 1.4-
Ethers such as dioxane, ketones such as methyl ethyl ketone and cyclohexanone, aromatic hydrocarbons such as toluene and xylene, aprotic polar solvents such as N,N-dimethylformamide, acetamide, N-methylpyrrolidone and dimethylsulfoxide, acetic acid Ethyl, esters such as methylcellosolve acetate, methylene chloride, 12
- Solvents such as chlorinated aliphatic hydrocarbons such as dichloroethane and chloroform, chlorinated aromatic hydrocarbons such as monochlorobenzene, and mixed solvents thereof.

The blending ratio of polyarylate to zinc oxide is in the range of 5 to 400 parts by weight per 100 parts by weight of zinc oxide, but from the viewpoint of the mechanical strength and repeated durability of the photoreceptor, the blending amount is 50 parts by weight or more. is promising. Further, the compounding ratio of the compound represented by the general formula (11) is required to be 5 parts by weight or more per 100 parts by weight of zinc oxide.

If the amount is less than 5 parts by weight, the effects of the present invention cannot be obtained.

In preparing the coating solution for the photoconductive layer, it is desirable to dissolve the polyarylate and the compound represented by the general formula (n) in a dispersion solvent in advance.

For preparing the photoconductive layer coating solution, a coating dispersion device such as a ball mill, sand mill, attritor, three-roll mill, Keday mill, or colloid mill can be used. As a method for applying the coating liquid to the conductive support, any coating method such as a blade coating method, a rod coating method, a knife coating method, a dip coating method, a spray coating method, etc. can be used.

The thickness of the photoconductive layer formed on the conductive support as described above is 5 to 100 μm, preferably 10 to 5 μm.
This is Ottm.

The zinc oxide photoreceptor of the present invention has the above structure,
It has the following features compared to conventional zinc oxide photoreceptors.

■) The polyarylate binder in the present invention has strong film-forming properties, has a rigid main chain, and has a glass transition point of 20
It has excellent physical properties such as dimensional stability and wear resistance, chemical properties such as heat resistance and ozone resistance, and electrical properties such as dielectric breakdown voltage and arc resistance.

Furthermore, high photosensitivity is maintained even if the blending ratio of polyarylate to zinc oxide is significantly higher than before. Therefore, the photoreceptor of the present invention has excellent chemical stability and mechanical strength, and its repeated durability is significantly improved.

2) This photoreceptor has excellent film properties and mechanical strength, and is compatible with a blade cleaning mechanism.

3) Addition of compound (II) eliminates the induction effect of photodischarge, so that a zinc oxide photoreceptor with extremely high sensitivity can be obtained.

By adding the compound (II), a zinc oxide photoreceptor can be obtained which has chargeability and photosensitivity to both positive and negative polarities and has excellent repeat durability.

5) It is possible to produce a zinc oxide photoreceptor that has excellent repeat durability, charging ability for both positive and negative polarities, and photosensitivity without requiring special materials and/or special processes.

Therefore, the electrophotographic photoreceptor of the present invention can be applied to a PPC type electrophotographic copying machine, and can be applied to any PPC type electrophotographic copying machine using the Carlson type, without being particularly limited by charging polarity. Furthermore, it is most suitable as a photoreceptor for PPC type microfilm reader printers that produce copies from negative and positive microfilms. It is also applicable as a photoreceptor for a two-color color copying machine or a photoreceptor for a PPC type color print making machine.

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples, but the embodiments of the present invention are not limited by these examples.

Preparation of sensitized zinc oxide 1.0 parts by weight of tetraiodofluorescein is added to 100 parts by weight of tetrahydrofuran and completely dissolved. Next, add zinc oxide powder (ZENOX 4 manufactured by Sakai Chemical Industry Co., Ltd.) to this solution.
000) was added, and the mixture was placed in a porcelain ball mill and mixed and dispersed for 3 hours. Next, the obtained coating liquid is transferred to a beaker, and the tetrahydrofuran is completely evaporated while stirring at 70°C. The zinc oxide powder dyed with tetraiodofluorescein thus obtained was used as a sensitized zinc oxide in the following Examples and Comparative Examples.

Example 1 10% of water-soluble polyvinyl butyral (manufactured by Eslenoku W2O1 Sekisui Chemical ■) was applied to the atsubenium side of a laminated film made by bonding polyethylene terephthalate and aluminum together.
Coating a wt% aqueous solution using a blade coating method,
Dry at C for 1 minute to form an intermediate layer with a thickness of 1 μm.

On the other hand, polyaryl) (ester copolymer represented by B(1): trade name U Polymer 100 manufactured by Unitika)
10 g was dissolved in 1001 nl of methylene chloride, then exemplified compound 10.9 represented by C1l was added and completely dissolved. Next, the sensitized zinc oxide 1 was added to this solution.
0 g is added and the mixture is dispersed in a porcelain ball mill for 2 hours. The obtained coating liquid is applied onto the above-mentioned intermediate layer by a blade coating method and dried at 90° C. for 1 minute.

The thickness of the photoconductive layer formed is 20 microns.

For the electrophotographic photoreceptor obtained as above, an electrostatic copying paper tester [:5P-428 model ■manufactured by Kawanichi Denki Seisakusho] was used.
The electrophotographic characteristics were evaluated using Attach the sample to the test device and set the corona discharge voltage ±5. QKV scanning speed 25
Charge under the conditions of 0++++n/second, and the potential immediately after charging ■
. cv]. After dark decay for 5 seconds (potential v5[:vl), the exposure amount required to decay to 5 seconds, that is, the half-reduced exposure amount E! A [lux·sec] was recorded as the photosensitivity, and it was measured as the surface potential after 60 lux·sec irradiation. On the other hand, during light irradiation, a differential circuit is used to calculate the photodischarge rate of 1-
1 was observed, and the time tmax from the start of light irradiation ('t=o) t until the photodischarge rate reached the maximum was measured, and this was used as a measure of the induction effect.

The smaller tmax is, the less induction effect the photoreceptor has.

As a result, the electrophotographic photoreceptor of this example had V□: +560 V, E3(: 3.9/l/7) when positively charged.
x seconds, Vr: +5V, tmax: 0.0
Second, Negative Charge Table 2.0 shows that the addition of Compound C42 increases the positive and negative charge potentials in proportion to the amount added, and also improves the photosensitivity during positive and negative charge and the residual charge during positive charge. A decrease in potential was observed, and the photoreceptor of the present invention (3
-2 to 3-6) are found to have excellent properties.

Example 4 In Example 1, exemplified compound C11 was replaced with Table 3.
Example 1 except that the compounds listed in Example 1. Electrophotographic photoreceptors 4-1 to 4-5 of this example were prepared by the same operation as above. Table 3 shows the properties of the photoreceptor obtained.

Table 3 All of the photoreceptors of this example exhibited excellent characteristics.

Example 5 Example 1. Example 1 except that the support was replaced with an aluminum drum, C45 was used instead of C11O as the exemplary compound, and dip coating was used as the coating method. Two electrophotographic photoreceptor drums of this example were prepared in the same manner as described above. An RPC copying machine (experimental machine) with one of the above trams equipped with a blade cleaning mechanism and with selectable corona charge polarity.
The surface potential is raised to +500■ by the positive charging process.
A running test was conducted in a repeating mode of charging, image exposure, two-component dry development, plain paper transfer, AC static elimination, and blade cleaning. As a result, good image characteristics were shown up to 10,000 cycles. Next, replace the photoreceptor drum and use a negative charging process to raise the surface potential to -500V.
A running test was conducted using the same procedure as the positive charging process described above.

As a result, good image characteristics were shown at a speed of up to 10,000 mm.

Comparative example 1゜Example 1. Example 1 except that a compound represented by the following formula was used in place of exemplified compound C1l. An electrophotographic photoreceptor of this comparative example was prepared in the same manner as above, and its electrophotographic properties were evaluated. As a result, when positively charged, VO: +200 V,
E 34: oo, Vo knee 120 in negative charge
V, E%: 5.3 lux·sec, and a sufficient charging potential could not be obtained.

Comparative Example 2 Example 1. In , vinyl chloride-vinyl acetate-maleic anhydride copolymer (VMCC) was used instead of polycarbonate.
Example 1 except that a 1:1 mixture of isobutyl acetate and dichloromethane was used instead of dichloromethane as the solvent. An electrophotographic photoreceptor of this comparative example was prepared by the same operation as described above, and its electrophotographic properties were evaluated. As a result, Vo: +6 in positive charging
50Vr, E54: 28 Lux sec, VR: 96
V, tmax: 2.6 seconds, Vony 700 V, E3,6: 21 lux·sec, vlI: 0■, tmax: 2.5 seconds when negatively charged, and the light sensitivity was slow.

patent applicant Tomoekawa Paper Mill Co., Ltd.

Claims (1)

[Scope of Claims] 1) An electrophotographic photoreceptor having at least a photosensitive layer provided on a conductive support, wherein the photosensitive layer is made of zinc oxide and has the formula (I) H3 (where n is an integer of 20 to 20'O). ), and a thermoplastic aromatic polyarylate represented by the general formula (II
) (In the formula, R1, R2, R3, and R4 are hydrogen atoms, substituted or unsubstituted alkyl groups, cycloalkyl groups, alkenyl groups, or aryl groups, R5 and R6 are hydrogen atoms,
Substituted or unsubstituted alkyl group, cycloalkyl group, alkenyl group, cycloalkenyl group, or aryl group, R7, R8, R9, RIO are hydrogen atoms, hydroxyl group, substituted or unsubstituted alkyl group, cycloalkyl group, alkenyl R5 and R6 may be cyclized with each other to form a saturated or unsaturated hydrocarbon ring having 3 to 10 carbon atoms. ) An electrophotographic photoreceptor comprising a compound represented by the following as an active ingredient. 2) The electrophotographic photoreceptor according to claim 1, wherein the compounding ratio of the compound represented by the general formula (n) is 5 parts by weight or more per 100 parts by weight of zinc oxide.